1. Field of the Invention
The present invention generally relates to closure means for containers and more specifically to an air-tight snap closure for allowing re-opening and re-closing of a container for keeping the freshness of the container contents.
2. Discussion of the Related Art
Various off-the-shelf goods, such as food products, are distributed in sealed packages to ensure that the package was not opened before purchasing, to prevent spillage of contents and to prevent exposure of the package contents to ambient atmosphere. For various food products it is also common to seal the package under vacuum, as is well known in the art, for better protecting the products. Once purchased, the initial seal is broken in order to access the package contents. However, many times the contents of the package are not consumed immediately but over a period of time. For this reason, there exist various secondary closure means which allow re-closing and re-opening of a container after the container is first opened and serves both for preventing accidental spillage of the contents and for keeping the freshness of the contents by minimizing the exposure of the container contents to air. Re-closable closures appear in different forms and may be provided either as an integral part of the container or as a separate unit. One family type of such closures comprises two compatible parts deposited on opposite walls of a container which when pressed together form a tight sealing. The two parts may be secured either on the inner or on the outer surfaces of the container walls. In the first case, when closed, the two closure parts are in immediate contact with each other. In the second case, the walls of the container are interposed between the closure members. External closures have some advantages to internal closures. External closure can be attached to a container after it has already been filled and sealed while inner closures can be attached only to empty containers, thus, the step of securing an inner closure must be integrated into the packages production line. Securing an external closure to a package, on the other hand, can be performed at a later stage, hence offering more flexibility. Furthermore, internal closures do not fit for some goods, such as for example powder-like products, which tend to accumulate on the closure surface, hindering the closure operation.
Known external closure means, although superior to inner closure, still suffer from a number of drawbacks. One such a drawback is the limit to the separation that can be obtained between the two opposite walls of the container for forming a mouth or an opening sufficiently large to allow convenient access to the container contents This drawback is particularly crucial for bags known in the art as non-gusseted bags, where the two walls of the container are directly connected to each other with no intermediate side walls. Another drawback is the extent of the force that should be applied in order to separate the two parts of the closure. Yet another drawback is that for non-gusseted packages a continuous pressure should be applied to the closure in order to maintain the closure in the open position.
Accordingly, it is the object of the present invention to provide an air-tight closure means for containers which can be used with any container and in particular with non-gusseted as well as with gusseted packages and which is easily opened without applying much forces.
It is another object to provide such a closure which when opened forms a well defined mouth or an opening that remains open with no need to apply further pressure by the user.
It is another object of the invention to provide such a closure that is inexpensive and is easily produced and applied to any container.
Other advantages of the invention will be apparent from the following description.